Save data tables with modelled HST colour trans

Model tables are saved in androphotsys/data (if the model scripts are
run from the package root, the tables are place automatically).

The goal is to have the color transformation codes read these tables to
get their coefficients, rather than hard code them.
HST colour transformations now read from table

Tables are generated using the modelling scripts in `scripts/` and data
tables are stored in `androphotsys/data`. Use the
`query_colour_transformation` function to get the transformation
coefficients.

This system means less degree for error in hard coding coefficients, and
it also becomes easier to print out a table of these coefficients too
for publication.
Make latex table of HST color transformations
Move HST->Cousins transformations to hst_cousins module

These are largely legacy; go with FSPS models instead.